Lignin Deoplymerisation Strategies Towards Valuable Chemicals and Fuels
Microalgae for sustainable production of fuels and chemicals
Transcript of Microalgae for sustainable production of fuels and chemicals
Microalgae for sustainable production of fuels and chemicals
Yusuf Chisti
School of EngineeringMassey University, Palmerston North
New Zealand
Outline
2. Microalgae biomass production options• Raceways and photobioreactors
4. Production of algal biodiesel – an example product
5. Summary and conclusions
3. Photobioreactor engineering aspects
1. Why microalgae?• Potential products• Advantages of using algae
Microalgae and cyanobacteria
Aquaculture
Why microalgae?
Speciality chemicals & materialsNutraceuticals/pharmaceuticals
• PUFAs• β-carotene
Pigments and colorants• Astaxanthin
Others• Insecticides• Nanomaterials
Agriculture• Biofertilizers• Soil inoculants
Environment• Wastewater treatment
Animal feed
Microalgae
Energy options from algaeBiogas – methane
• Anaerobic digestion
Bioethanol• Fermentation
Biodiesel – microalgal oils• Liquid hydrocarbon fuels• Jet fuel
Biohydrogen• H2 fuel cells
H2
O2
H2O
1. Direct conversion of sunlight to a bioproduct
2. Renewable and sustainable production
3. Rapid growth compared to most plants
4. Little or no competition for agricultural land
5. No competition with food/feed supplies
6. Low requirement for freshwater
Advantages of microalgae
Microalgal biomass productionOption 1: Raceway ponds
Paddlewheel
Typical biomass productivity0.025 kg m−2 day−1 (∼82 tons ha−1 year−1)
Maximum biomass concentration1 kg m−3 (0.5 kg m−3 typical)
Chlorella, Japan
β-carotene, Australia
Option 2: Tubular photobioreactors
Microalgal biomass production…
Proved biomass productivity1.535 kg m−3 day−1 (∼158 tons ha−1 year−1)
Biomass concentration4 kg m−3
A tubular photobioreactor
Degassingcolumn
Exhaust
Air
Harvest
Freshmedium
Solar array
Pump
Coolingwater
Photobioreactor engineering issues to be addressed
Photoinhibition
Irradiance, I0 2 4 6
μ
0
1 μmax
Photoinhibitedgrowth
Fluid mechanics• Shear sensitivity of cells
• Mass transfer • Temperature control
Irradiance
Growth kinetics
nav
navmax
IKI
n +⋅
=μμ
Mass transfer• CO2 supply• O2 removal Thermal engineering
• Temperature control
Culture medium
Flashing light effect
United States biodiesel needs = 0.53 billion m3
(to replace all transport fuel)
Crop Oil yield(L/ha)
Land area needed (M ha)
Percent of existing US cropping area
Corn 172 3,080 1,692 Soybean 446 1,188 652 Canola 1,190 446 244 Jatropha 1,892 280 154 Coconut 2,689 198 108 Oil palm 5,950 90 48 Microalgae 35,202 15.2 8 Microalgae 70,405 7.6 4
20% w/w oil in biomass
40% w/w oil in biomass
Not feasible
Biodiesel – a potential product from algae
Animal feedOther productsEffluent
• Fertilizer• Irrigation
Algal biomass production
Biomass recovery
Power generation
Biomass extraction
Anaerobic digestion
Algal oil Biodiesel
Biogas
CO2
Water + nutrients
Power togrid
Power to biomass process
LightCO2
H2O/nutrients
Microalgal biodiesel process concept
A necessary stepBiogas quality: 16.2–30.6 MJ m−3
Yield: 0.15–0.65 m3 kg−1 dry biomass
Summary and conclusions1. Products and energy options from microalgae
• Advantages of using microalgae
3. Photobioreactor engineering issues
2. Microalgal biomass production• Raceways and photobioreactors
5. A self sustaining process for producing algal oils
4. No terrestrial plant can provide sufficient biodiesel to fully displace fossil transport fuels, but algae can